Loop-takers for sewing machines



Nov. 18, 1958 w. c. VAN NESS 2,860,591

LOOPTAKERS FOR SEWING MACHINES 2 Sheets-Sheet 1 Filed July 22, 1954 INVENTOR.

William 6. Van Ness WITNESS BY ATTORNE Y Nov.- 18, 1958 w. c. VAN NESS LOOP-TAKERS FOR SEWING MACHINES 2 Sheets-Sheet 2 Filed Jply 22. 1954 INVENTOR. William C. Van ess ATTORNEY WITNESS 2,866,591 Patented Nov. 18, 1958 LOOP-TAKERS. FOR SEWING. MACHINES William C. Van Ness, Devon, Conn., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application July 22, 1954, Serial No. 444,998

Claims. (Cl. 112-201) The present invention relates to a single-thread chainstitch sewing machine having a rotary wing-type looper and has for a primary object to provide in such a machine improved and simplified means for sewing a seam with loose stitches.

It has heretofore been the practice in sewing a loosestitch seam to employ a thread-nipper which prevents the take-up mechanism from withdrawing the normal excess thread from the stitch and thus properly setting the same. Such a machine is disclosed, for example, in the U. S. patent of Becker, No. 2,328,705. In accordance with the present invention, it has been found that substantially the same result can be obtainedwithout-the use of a thread-nipper as heretofore, but with a modified looper as hereinafter set forth.

Having in mind the above and other objects: that will:

rangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read'in conjunction with the accompanying drawings in which:

Fig. 1 is a head end elevation view, partly in section, of a sewing machine in which the present invention has been incorporated;

Figs. 2, 3 and 4 are semi-schematic views similar to Fig. 1 but on a reduced scale and ,illustratingthe elements in successively different positions of actuation;

Fig. 5 is a detail elevation view of the looper per se.

Fig. 6 is a detail section view of a. thread controller on the machine illustrated in Fig. 1.

Figs. 7 and 8 are views of the seams that can be produced by the machine of Fig. 1, Fig. 7 illustrating a loose seam and Fig. 8 illustrating a tight seam.

In the drawings there is illustrated asewing machine having a frame includinga bed 1 and a head 2 overhangingthe same and having the open end thereof closed'by. a plate 3 secured to the headby screws 4. The various mechanisms of the machine are herein illustrated and describedonly insofar as is necessary to obtain a full understandingof the present invention. These mechanisms may be of conventional construction, such as illustrated in the U. S. patent of Zonis et al;, No. 2,332,125, to-which reference may be had'if desired for a more'complete disclosure thereof. i i

Journaled' longitudinally of the frame of the machine is a main or bracket-arm shaft Shaving secured to the end thereof a counterbalanced crank 6. The crank 6 carries acrank-pin 7 that is connected by means of a link 8 to a collar 9 in a needle-bar 10 which is journaledin the head 2 forvertical reciprocation and which carries a needle ll at its lower end. It will be obvious that upon rotation of the shaft 5 the needle-bar 10 will be reciprocated' in the usual fashion.

A throat-plate 12*is provided. in the beds 1' at: the point of. stitch formation, whichthroat-plate has formedtherein journaled longitudinally of the bed 1, andat the other end is formed with a fork 19 which embraces a pin 20 at the free end of a feed-lift crank 21 secured on a feedlift shaft 22 also journaled longitudinally of the bed 1. The work W is urged into engagement with the throatplate 12 and feed-dogs 15 by a conventional presser-rnechanism including the usual presser-bar 2-3 slidably mounted in the head 2 and carrying a resser-foot 24 at' the lower end.

In addition to the needle mechanism, the stitching mechanism of the machine includes a rotary wingtype looper 25 that is mounted upon the end of a looper-shaft journaled longitudinally of the bed 1 and driven at a ratio of one-to-one relative to the shaft 5. This mechanism, while not herein illustrated, is fully disclosed in the above noted patent of Zonis et al'. to which patent reference is made. The looper 25, which is illustrated per se in Fig. 5, is hereinafter more fully described.

The needle-bar 10 has secured thereto a collar 26 supporting a take-up arm 2'7 thatextends througha slot 28 in the plate 3 and is provided with an eye 29. Secured to the head 2 is a conventional disc-type tension 30 comprising astud 31 projecting from the head 2 and supporting a pair of tension discs 32 and a bee-hivespring. 33, and having threaded thereon an adjusting nut 34 which provides for adjustment of the compression of the spring 33 and thus varies the tension thereby imposed upon a stitching thread T passing therethrough.

There are provided a plurality of thread guides comprising a multi-eye guide 35, a drum-like guide 36, an adjustable guide 37 and a thread'controller 38. The guide 37 is provided with a shank 39 having a slot 40fand" is adjustably secured tothe plate 3 by screws 41' that extend through the slot 40. The thread. eye in the guide 37 is formed in an arm 42 extending outwardly. from the shank 39. The thread-controller 38, which is illustrated per se in section in Fig. 6, is secured to the head 2 by one of the screws 4 that extends through a shank 43L thereof. The shank 43 carries a cup 44 in which is telescopically arranged an opposed cup 45. A stud 46 extends from and centrally of the bottom of the cup 44, which stud is surrounded by a very light coil spring 47 which urges the cup 45 outwardly of the cup 44; The outer end of the stud carries a stop 48 that limits the movement of the cup 45 and against which it pinchesthe thread T to impose a light tension thereon. A thread-eye 49 having an entrance slot 50 is formed in the stud 46.

The looper 25, as hereinbefore pointed out, is a rotary wing type looper that is adapted to cooperate with the needle 11 in concatenating the thread I ina single-thread chain-stitch. The looper 25 is provided with a loop-seizing beak 51 formed on a loop-expanding body 52 having a leading edge 53' and a trailing edge 54; A. loop-detaining tail 55 is formed upon the peripheral extremity of the body 52 opposite the beak 51. i The edges 53 and 541 are convergent generally toward the center ofrotation, designated as. the point C, and toward a loop-detaining throat 56. Opposite the loop-expanding body 52is a loop-twisting and spreading wing 57.

In. operation, thethread T, which is drawn from any suitable source of supply, is first threaded through the eyes of the guide 35, then about the guide 36; through the tension 30, the guide 37, the take-upwarmi 27, the controller 38, and finally through the eye of the needle 11. In the usual manner, the beak 51 will pass through the loop of the thread T cast by the needleand through last-seized loop of thread will, as it is being expanded slide onto the leading edge 53 of the loop-expanding body, Fig. 3, and then, it is twisted and spread by the wing 57 as it slides into the throat 56. In the meantime, the previous loop, which was in the throat 56, will slide onto the trailing edge 54 of the body 52 and then onto the loop-detaining tail 55 from which it is finally cast-' off.

The timing of the machine is such that loop-seizure occurs after substantially 30 of rotation of the shaft from the position of maximum needle penetration, during which time the thread loop is cut out by the needle. With reference to Fig. 8, it will be seen that the extremity of the tail 55 of the looper is spaced at about 150 angularly about the center of rotation C from the extremity of the beak 51. In addition, the tail 55 is formed to detain the loop until it has been rotated to substantially the position in which the beak was during loopseizure. Thus, cast-off of the thread loop is made to occur at substantially the time that the needle-bar has reached its position of maximum rise, and because the take-up 27 consists of an arm carried by the needle-bar, the take-up will also be at its position of maximum rise. The feeding mechanism which also effects a takeup function, is also operative during this portion of the cycle. Consequently, there will be substantially no takeup action after cast-off and the thread which is in the stitch at the time of cast will remain substantially unchanged. In accordance with the above, the looper functions as a thread measuring means which effectively measures the amount of thread in each stitch.

It will, of course, be obvious that, as that take-up 27 is rising, and since it is unable to draw thread from the stitches or the loops about the looper, it will snub the loops about the loopers to a degree determined by the setting of the tension 30, and will thereafter maintain the seame in this stressed condition while at the same time drawing thread into the system from the supply through the tension 30. In order that the thread will be drawn in from the supply at a rather uniform rate, the trailing edge 54 of the looper body 52 is formed to give up thread at a rate which, considering the requirements of the beak 51 which is at the same time expanding a second loop and the requirements of the rising takeup, will result in a uniform deficiency of thread in the system.

By adjusting the tension 30, it will be seen that the thread loops will be snubbed either tightly or loosely about the looper. In this manner, the illustrated machine may be adjusted to sew either a normal seam as illus trated in Fig. 8 ma loose-stitch seam as illustrated in Fig. 7. It should be noted that to obtain a normal seam, as in Fig. 8, the tension 30 is set at about what would be considered normal in similar machines as heretofore constructed, and to obtain a loose-stitch seam, the tension is substantially reduced to the point where it imposes a very light drag on the thread. While the take-up is herein illustrated and described as reaching its maximum rise at the time of loop cast-oif,-it is contemplated that, in practice, cast-off will be made to occur at a point in the cycle which is several degrees of rotation before the time of maximum take-up rise. Since at this time the tangential motion of the crank-pin 7 is almost perpendicular to the axis and path oftravel of the needle-bar, there will still be very little take-up action after cast-off. While small, this take-up action is useful in sewing a normalstitch seam, as in Fig. 8, but will have little effect upon the loose-stitch seam as in Fig. 7.

It will also be noted that the tail 55 is disposed radially with respect tothe center of rotation C at a distance greater than that of the beak 51. This expedient also aids to control the thread loop before cast-off and re- 4 duces the minimum amount of thread that can be measured for each stitch, which is particularly useful in sewing a tight-stitch seam.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which I is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is:

1. A rotary wing-type looper for a sewing machine comprising a body having a loop-seizing beak and a loop-detaining tail, said body converging generally from said beak and tail toward the center of rotation of said looper and toward a loop-detaining throat formed in said looper, a loop-twisting and spreading wing extending from said throat to the opposite side of the center of rotation of said looper from said body, said tail being spaced substantially 150 degrees angularly about the center of rotation of said looper from said beak.

2. A rotary wing-type looper for a sewing machine as set forth in claim 1 in which said tail is spaced radially from the center of rotation of said looper a distance greater than that of said beak.

3. In a sewing machine having a reciprocatory needle, a rotary wing-type looper cooperating with said needle in the formation of single-thread chain-stitches, a takeup for performing a take-up action on a sewing thread i and having a position of maximum action, said looper having a loop-seizing beak and a loop-detaining tail, said beak being designed to enter a loop of thread cast by said needle, and said tail being designed to have a loop of thread held thereon until cast-off, said tail being spaced substantially degrees angularly about the center of rotation of said looper from said beak, said looper being timed to cast-off the loop held by said tail at substantially the time said take-up reaches the position of maximum action, and a variable thread tension acting to impose a drag upon the thread and being disposed relative to the lead of the thread in advance of said take-up.

4. In a sewing machine, a bed, a head overhanging said bed, stitch-forming mechanism comprising a needlebar mounted in said head for endwise reciprocation and carrying a needle at its lower end and a rotary wingtype looper mounted for rotation in said bed, said looper cooperatingwith said needle in the formation of singlethread chain-stitches and having a loop-seizing beak for entering a loop of thread cast by said needle upon rotation of said looper during stitch formation, a take-up mechanism mounted in said head and having a position of maximum action, a variable thread tension device disposed in advance of said take-up relative to the lead of the thread for imposing a drag upon a thread run therethrough, means for actuating said needle, looper and take-up in timed relation to effect stitch formation, and means on said looper spaced angularly from said loop-seizing beak for holding a loop of thread during a portion of the stitching cycle while said take-up is operative and for releasing said loop at substantially the time said take-up reaches the position of maximum action.

5. In a sewing machine, a bed, a head overhanging said bed, stitch-forming mechanism comprising a needlebar mounted in said head for endwise reciprocation and carrying a needle at its lower end and a rotary wingtype looper mounted for rotation in said bed, said looper cooperating with said needle in the formation of singlethread chain-stitches, a take-up mechanism mounted in said head and having a position of maximum action, a

variable thread tension device disposed in advance of said take-up relative to the lead of the thread for impos ing a drag upon a thread run therethrough, said looper having a loop-seizing beak and a loop-detaining tail spaced angularly relative to said beak, means enabling said looper to be actuated in timed relation with the actuation of said needle and take-up mechanism with the beak passing adjacent the needle in its loop-seizing action and the tail passing through the position assumed by said needle during loop-seizure when the take-up has reached its position of maximum action whereby the tail will hold a loop of sewing thread during a portion of the stitching cycle while the take-up is operative and References Cited in the file of this patent UNITED STATES PATENTS 783,411 Bigelow Feb. 28, 1905 1,316,022 Fifield Sept. 16, 1919 2,328,705 Becker Sept. 7, 1943 2,345,327 Clayton Mar. 28, 1944 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Non 2,860,591

November 18, 1958 William C, Van Ness equiring correction and that the said Letters read as corrected below.

Column 3,

line 15 for "out" read same read ma east line 40, for "seame" Signed and sealed this 31st day of. March 1.9590

(SEAL) Attest:

KARL H, AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents 

